Special Horticultural Practices in Flower Crops

Introduction

In a garden there are certain operations that are to be followed judiciously for successful cultivation of flowers and ornamental plants, most of these operations, such as pinching, deshooting, disbudding, desuckering etc, are of vital importance for the growth of the plants. These operations are generally known as special horticultural practices.

Special Horticultural Practices

Stopping and pinching
Deshooting
Disbudding
Desuckering
Defoliation
Wintering
Staking
Mulching
Prunin
Repotting
Forcing

Stopping and pinching

The operation of pinching or stopping involves the removal of the growing-point of a shoot along with a few leaves. The main purposes of pinching are:-

To encourage branching to produce a bushy growth.
To increase the production of flower-buds on the branch which is pinched.
Pinching is done at a stage when the plants are young and between 7 and 15 cm in height, depending on their habits of growth.
The plants which need pinching include dahlia, chrysanthemum, marigold, carnation, rose.

A. Chrysanthemum

Pinching is performed both in suckers and in cuttings.
It is normally done with thumb and forefinger.
Pinching is most essential for small flowered chrysanthemum.
First pinching is done when the plants reach a height of 15-20 cm with 3-4 pairs of leaves.
A second pinching may be necessary if the plants make straggly and lean growth
Two types of pinching are performed in chrysanthemum.
In soft pinching the soft tip of the shoot along with 2-3 open leaves is removed while in hard pinching a longer portion up to hard shoot is removed.
In case of standard chrysanthemum only single bloom on a branch is usually allowed to produce.
The pinching is not done if only one central bloom is desired on the main branch.
Single pinching is done, if two flowers are desired, whereas double pinching is done for four flowers
In spray chrysanthemum numerous small to medium sized flowers are produced, therefore, two pinching are required to encourage lateral growth.
As a general rule rooted cuttings are pinched 2 weeks after planting or approximately 100 days before full bloom.

Pinching in chrysanthemum

B. Rose

Pinching in rose is generally practiced to adjust flowering for a particular season.
An examination of the rose stem will show that below a flower bud there is strap shaped leaf followed by 3 leaflet and 5 leaflet leaves, in the axils of which there are a reasonably long stem, pinching has to be done above a 5 leaflet leaf with a rounded bud.
The shoots selected for later flower production, are pinched by removing 3-5 cm of terminal growth, after at least 15 cm growth is formed.
These shoots may again be pinched after 4-6 weeks.
This procedure of pinching prevents flowering and encourages the plants to form new growth the base

C. Carnation

There are three ways of pinching in carnation.

Single pinching
Pinch and a half
Double pinching

Single pinch is done once at 5 node stage by retaining 4-5 shoots for obtaining early crops.
Second type of pinching is pinch and a half. In this type of pinch, the main stem is pinched and later when the resulting shoots are long enough, half of largest shoots on each plants is pinched.
Double pinching is done in carnation, first by doing single pinch followed by another pinching of all the shoots when they are 6-8 cm in length.

Pinching in carnation

D. Marigold

Marigold plants grow straight upward to their final height and develop into terminal flower buds.
After production of terminal flower bud, side buds become free from correlative inhibition of apical dominance and these buds develop into branches to produce flowers.

If the terminal portion of shoots is removed early, that is 40 days after transplanting, emergence of side branches starts earlier and more number of flowers of good quality and uniform size are produced.

Deshooting

Deshooting involves the removal of shoots that are not wanted.
Some flowering annuals and herbaceous perennials produce numerous side shoots and if all of them are allowed to lower, the size and quality of the flowers will be greatly reduced.
Only a specific number of side shoots are allowed to flower and the others are removed at an early stage.

Deshooting in carnation

Chrysanthemum

Deshooting is practiced from time to time by removing all side shoots before they attain the size of 2.5 cm.

Carnation

It is found to influence flowering in carnation.
Removal of all secondary shoots from 5 week after planting and on alternate days till flowering does not affect the stem lengths but stem size and flower size is increased by 10-15 per plant
Disbudding
To produce large specimen bloom, the flower buds per stem must be restricted to one.
For this, the central or crown bud is retained and the buds or side shoots clustered around the central bud are removed.
Flowers become small if all the buds are allowed to open.
In many plants several superfluous bud, flowers, and shoots develop in the axils of the main stems and branches.

Chrysanthemum

Disbudding method varies according to the type of chrysanthemum grown.
Many of the varieties are disbud or standard types, in which the largest terminal bud is retained and all axillary buds are removed.
Disbudding of spray varieties is very easy because in this case only the large apical bud is removed and the axillary buds are allowed to develop.

Disbudding chrysanthemum

Rose

The disbudding must be done regularly and also as soon as possible in order to avoid large wounds in the upper leaf axil.
For most spray varieties, the center crown bud is to be removed.
In hybrid Tea roses only one or at best two buds should be allowed to flower upon each shoot so as to have a large sized bloom.
All other buds, should be removed or disbudded.

Carnation

In standard carnations, side buds should be removed whereas in spray carnations, the terminal bud has to be removed.
It is when the axillary flower buds are in pea size.

Dahlias

Dahlia will generally have three flower buds at the end of each branch.
The central or “crown” bud is retained for blooming while the other two are removed at “pea” stage.
If the crown bud is damaged, one side bud has to be retained in place of the central bud.

Disbudding in dahlia

Desuckering in chrysanthemum

During the vegetative growth phase, plant grows upward and new suckers continue to develop from the base of the plants
For preventing improper and vigorous growth of plant, suckers are removed from time to time.
Without Desuckering, the plant will loose vigour and becomes week.

Defoliation

The removal of foliage is known as defoliation.
This is done mainly with a view to inducing flowering in certain plant
This can also be done to reduce transpiration loss during periods of stress and strain and also during transportation of certain plants such as roses.
Defoliation can be achieved by the removal of leaves by hand or by the use chemical and withholding water.

Jasmine

Various chemical defoliants reduced the apical dominance and encouraged lateral shoots.
Pentachlorophenol and sodium chloride sprays increased flower yield than un pruned plants of Jasminum grandiflorum.
Application of 3000 ppm of pentachlorophenol was found more effective in flower production in Jasminum grandiflorum.

Wintering in rose

This may be considered as an alternative to root pruning. In the hotter parts of India it may not be wise to resort to root pruning.
In such places ornamental plants are “wintered” . Flowering shrubs such as rose and jasmine can be wintered in northern and eastern India.
During resting period the water supply to the plant to be wintered is stopped for a few days and the roots are exposed to the sun by removing the surface soil around the trunk.
The duration of exposure varies from three to fifteen days depending upon the age, the nature, and the hardiness of the plant.
After this the roots are covered with the same soil enriched with farm yard manure and copiously watered.

Bending in rose

Leaf is a source of food for every plant.

There should be balance between Source (Assimilation) and sink (Dissimilation).
After planting, 2 to 3 eye buds will sprout on main branch.
These sprouts will grow as branches and these branches in turn form buds.
The mother shoot is bend on 2nd leaf or nearer to the crown region.
The first bottom break or ground shoot will start coming from the base.
These ground shoots form the basic framework for production and there on the ground shoots should be cut at 5th five pair of leaves and medium ground shoots should be cut at 2nd or 3rd five pair of leaves.

Staking

Plants in the garden, either in pots or on ground, need support at least for a parts of, or throughout, its life.
Selecting the proper stakes and fixing them aesthetically as well as purposefully is an art.
Stakes may be of various type.
The herbaceous plants do not require very strong stakes.
The most common stakes used in India are made of either whole bamboo or split bamboo of various sizes depending upon the type of plants to be stakes.

Carnation

Netting for plant support: 4 layers
1^stlayer: 7.5×7.5 cm.
2^ndlayer: 10×10 cm.
3^rdlayer: 12.5×12.5 cm.
4^thlayer: 15×15 cm.

Support Material

Carnation crop has the tendency to bend unless supported properly.
 Hence the crop needs support while growing.
Good support material is metallic wire woven with nylon mesh. 
At every two meters the wire should be supported with poles.
The poles at both the ends of bed should be strong.
Metallic wire is tied around the bed along the length with the support from supporting poles.
Across the bed, nylon wires are woven like net.
For an optimum support, an increasing width of the meshes can be used.
Bottom net can be of 10x10cm, then two nets of 12.5x12.5cm and the upper most can be 15x15cm.

Net Practicing in Carnation

Gladiolus

Especially large flowers varieties of gladiolus grown outdoor are susceptible to lodging, hence need staking.
The stem should be tied with strings to thin but strong supports
Earthing up of the plants, when the spike starts elongation, also provides sufficient to prevent lodging.
The plants should be tied loosely around the stem to allow further growth of plants.

Chrysanthemum

The lateral are staked with strong split bamboo stakes inserted in the compost with a view to given support and also see that these are spread out from each other.
The first crown bud develops at the end of each lateral which contains maximum number of ray florets and will be give the largest bloom, though may not be the best bloom.

Mulching

The purposes of mulching are varied.
The intention is to regulate soil temperature, to conserve moisture, and to control weed.
There are several kinds of mulch such as straw, leaves, pulverized corn cobs, peanut hulls, cottonseed hulls, stable manure.
Polythene sheet and aluminum foils are also used as mulch.

Dahlia

Mulching is an important operation in dahlia cultivation.
This can be done with grass clippings, old hay and sawdust.
Mulching helps to maintain an even soil temperature, induces early flowering and better blooms.
It slows down water evaporation and reduces the irrigation requirement.

Gerbera

It can be done with the help of straw, polythene sheets, etc
It gives a good control of weeds and helps to conserve soil moisture.
The main disadvantage is that, it serves as a home for various insect and pests.

Mulching in Gerbera

Pruning

Pruning: - The planned removal of branches, twigs, limbs, shoot, or root is termed as pruning.

Principle of pruning:-

The main principle of pruning is to reduce the apical dominant & encourage the lateral branches to grow.
Objectives of pruning:-
A definite direction and shape to the plant.
Develop a strong framework
The aim of utilizing the available space effectively.
Pruning also influences productiveness and improves the quality of the product.

Root pruning:-

Root pruning is done to a limited extent in ornamental horticulture, as in the case of rose and jasmine.
The main effects of root pruning are (1) reduced absorption, (2) reduced top growth, and (3) more branching in the root system.

Jasmine

Pruning is an important cultural practice in jasmine, which encourages growth of new healthy shoots and influences the flower yield.
In this regard, time and intensity of pruning are important.
In large plantations, pruning is done on different dates to get the harvest in well-spaced manner as otherwise all plants will start flowering at a time.
However, in Jasminum grandiflorum, December pruning is beneficial as maximum yield is obtained if the plants are pruned in this month ,and first picking could be done in March.
But all pruning dates in January and February delay the picking till May to June .
Jasminum auriculatum can be pruned during January to March to have flowers for longer duration, while Jasminum pubescenceshould be prune as soon as they finish flowering in early summer.
In Jasminum sambacpruning after normal flowering season stimulates another flush of flowers.
Jasmines are pruned by heading back all the past season ‘shoots at a height if 50 to 90 cm from ground depending upon the species and all the leaves from the remaining parts are stripped off.

Rose

Time of pruning:- In most parts of India, pruning is done during October.
Pruning in Hybrid Tea roses -end of first week of October.
Pruning in Floribundas - In the first season, pruning will be similar to that of hybrid Tea rose to encourage more growth from the base.
Pruning of standard roses -The pruning of standard roses is somewhat similar to that of bush rose. The aim should be to have a well-shaped plant with the crown growing symmetrically in all direction.

Repotting in Anthurium

It is done when the growing medium has deteriorated & when the plants have outgrown the pot.
The side suckers may be planted separately & the mother plant should be planted with the fresh growing medium.

Forcing in Lily

Forcing lily flower for normal durations, the bulbs require cold treatment at 2-4⁰C for 6 weeks in case of Asiatic hybrids and 8 weeks for the Oriental ones.
It is possible to use "frozen-in" bulbs which are kept at 1⁰C after pre-cooling treatment for off-season flowering.
A night temperature of 16 ⁰C with a day temperature below 21 ⁰C inside the greenhouse is recommended for forcing.

References:

Singh, A. K. (2006). Flower Crops Cultivation and Management. New India Publishing Agency New Delhi.
Randhawa, G.S. and Mukhopadhyay A. (1986). Floriculture in India. Allied Publ.

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Special Horticultural Practices in Flower Crops

Introduction